Fourier transform infrared spectra of a suite of coals of varying rank from peat to anthracite were obtained via reflectance micro-FTIR and traditional KBr pellet techniques. With increasing rank of ...coal samples, KBr-FTIR spectra exhibit rising aromaticity (ratio of CHar at 3000–3100 or 700–900cm−1 versus CHal at 2800–3000cm−1) and enhanced condensation of aromatic rings (ratio of CHar versus C=C at ~1600cm−1), whereas the aliphatic chain length (ratio of CH2/CH3 at 2800–3000cm−1) and the ‘C’ factor (ratio of C=O at ~1710cm−1 versus (C=O+C=C)) decrease. The ratio of CHal /(CHal+C=C) (i.e., the ‘A’ factor), which reflects the hydrocarbon-generating potential, initially rises at low rank and later decreases in higher-rank coal= (Ro >0.98%). However, the trends of these semi-quantitative FTIR ratios are difficult to trace in high-rank coals (Ro >1.50%), probably attributable to limited peak areas and enhanced uncertainties in ratio calculations. The overall evolutionary trends of functional group abundances in bulk coals and their individual macerals are similar; distinct differences in chemical properties, however, exist among maceral groups, and these variations depend on rank. Within the three maceral groups, liptinite generally exhibits the lowest aromaticity, the longest aliphatic chains having the least amount of branching, and the highest ‘A’ factor testifying to the highest hydrocarbon-generating potential. In contrast, inertinite shows the highest aromaticity and degree of condensation of aromatic domains and the lowest hydrocarbon-generating potential. Vitrinite generally exhibits intermediate characteristics between liptinite and inertinite.
Compared to KBr spectra, micro-FTIR spectra present better detection capability and stronger signals in the 700–900cm−1 region, which allows for close investigation of aromatic CHx out-of-plane deformation modes. The rapid decrease in the peak area ratio at ~870cm−1/~750cm−1 in vitrinite from peat to low-volatile bituminous coal is followed by a significant increase after Ro >1.50%, which indicates the dominance of highly substituted aromatic rings in immature coal's structure, while condensed aromatic domains become prevalent in higher-rank coals (semi-anthracite and anthracite). The increase in coal aromaticity during coalification is attributed largely to the accumulation of condensed aromatic structures in more mature coals. Novel reflectance micro-FTIR mapping is a promising and powerful tool providing high-resolution information on chemical properties of coal macerals relating to parent material and coalification.
► We demonstrate the applicability of micro-FTIR mapping to the study of coal macerals. ► Aromaticity increases and aliphatic chain length decreases with coal rank. ► Highly substituted aromatic rings dominate in immature coal’s structure. ► Condensed aromatic domains are prevalent in higher-rank coals.
Two sets of experiments, categorized as TG–FTIR and Py–GC–FTIR, are employed to investigate the mechanism of the hemicellulose pyrolysis and the formation of main gaseous and bio-oil products. The ...“sharp mass loss stage” and the corresponding evolution of the volatile products are examined by the TG–FTIR graphs at the heating rate of 3–80
K/min. A pyrolysis unit, composed of fluidized bed reactor, carbon filter, vapour condensing system and gas storage, is employed to investigate the products of the hemicellulose pyrolysis under different temperatures (400–690
°C) at the feeding flow rate of 600
l/h. The effects of temperature on the condensable products are examined thoroughly. The possible routes for the formation of the products are systematically proposed from the primary decomposition of the three types of unit (xylan, O-acetylxylan and 4-O-methylglucuronic acid) and the secondary reactions of the fragments. It is found that the formation of CO is enhanced with elevated temperature, while slight change is observed for the yield of CO
2 which is the predominant products in the gaseous mixture.
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•Model-free integral kinetics method and analytical TGA–FTIR were conducted on pyrolysis process of PKS.•The pyrolysis mechanism of PKS was elaborated.•Thermal stability was ...established: lignin>cellulose>xylan.•Detailed compositions in the volatiles of PKS pyrolysis were determinated.•The interaction of biomass three components led to the fluctuation of activation energy in PKS pyrolysis.
Palm kernel shell (PKS) from palm oil production is a potential biomass source for bio-energy production. A fundamental understanding of PKS pyrolysis behavior and kinetics is essential to its efficient thermochemical conversion. The thermal degradation profile in derivative thermogravimetry (DTG) analysis shown two significant mass-loss peaks mainly related to the decomposition of hemicellulose and cellulose respectively. This characteristic differentiated with other biomass (e.g. wheat straw and corn stover) presented just one peak or accompanied with an extra “shoulder” peak (e.g. wheat straw). According to the Fourier transform infrared spectrometry (FTIR) analysis, the prominent volatile components generated by the pyrolysis of PKS were CO2 (2400–2250cm−1 and 586–726cm−1), aldehydes, ketones, organic acids (1900–1650cm−1), and alkanes, phenols (1475–1000cm−1). The activation energy dependent on the conversion rate was estimated by two model-free integral methods: Flynn–Wall–Ozawa (FWO) and Kissinger–Akahira–Sunose (KAS) method at different heating rates. The fluctuation of activation energy can be interpreted as a result of interactive reactions related to cellulose, hemicellulose and lignin degradation, occurred in the pyrolysis process. Based on TGA–FTIR analysis and model free integral kinetics method, the pyrolysis mechanism of PKS was elaborated in this paper.
Zein films added with different concentrations (0, 25, 50, & 75 mg/ml of film forming solution) of pomegranate peel extract (PPE) were designed and characterized as a novel packaging material for ...Himalayan cheese (kalari). With increase in PPE concentration, tensile strength, elongation at break, total phenolic content and antioxidant activity of zein films increased whereas film solubility, water vapor transmission rate decreased and thickness remained constant. PPE containing films exhibited inhibitory activity against all tested pathogenic strains (Escherchia coli, Pseudomonas perfringens, Micrococcus luteus, Enterococci faecalis, Staphylococcus aureus, Proteus vulgaris and Salmonella typhii). ATR-FTIR spectra showed interactions between PPE polyphenols and zein film. Kalari wrapped in PPE containing zein films were found to have low protein and lipid oxidation products during storage when compared to film without PPE. Films were also found to inhibit spoilage microorganisms in kalari whereas number of Lactic acid bacteria was enhanced. The study validated that incorporation of fruit waste (pomegranate peel in this case) which are rich in polyphenols, in zein film offers a promising source for inducing it the ability to control cheese spoilage caused either by the bacterial contamination or protein and fat oxidation, without affecting its overall sensory characteristics.
•Packaging films with added pomegranate peel extract (PPE) were used for packaging of kalari cheese.•The film with added PPE retarded the cheese spoilage.•The film with added PPE retarded the oxidation of fats and proteins of cheese.•The film can be suggested as potential active packaging for fresh cheeses.
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•Effect of ultrasound on particle size, solubility, rheology, structure, thermal and morphology of WP was evaluated.•Modified WP showed significantly smaller particle size and higher ...solubility.•Ultrasound significantly improved thermal stability of WP as confirmed by the shift in HCT and transition temperature.•FTIR spectra and microstructure also confirmed significant impact of ultrasound on confirmation and structure of WP.•Study would diversify the application of whey protein as tailored food ingredient.
Ultrasound, an emerging non-thermal technique, has potential to modify the functionality of bio-molecules like protein. In the present study, the impact of ultrasound on whey protein (WP) was assessed with functional, rheological, heat coagulation and transition temperature, SDS-PAGE, FTIR spectra, scanning electron microscopy and transmission electron microscopy. The results of this study showed that the raw WP had broad bimodal particle size distribution while after ultrasonication, modified WP exhibited narrower distribution along with smaller particle size (0.683 ± 0.225 μm) compared to untreated WP (2.453 ± 0.717 μm). The solubility of WP also increased after ultrasonication (72.22 ± 0.68% to 79.21 ± 1.08%). During the rheological evaluation, both the samples exhibited Newtonian behaviour but, the modified WP exhibited dramatically higher storage modulus (G′) throughout the temperature profile compared to raw WP mainly due to enhanced proteins aggregation during heating which revealed more elastic and stronger gel. The modified WP exhibited significantly higher (about 6-times) heat stability compared to raw WP which signified that after ultrasonication the WP can withstand higher temperature during processing for longer time. The results were also confirmed by higher transition temperature (Tpeak) of modified WP (93.32°) compared to untreated WP (81.93 °C). The SDS-PAGE profile of raw and modified WP showed that the ultrasound significantly decreased the bands density of low molecular weight molecules (β-lactoglobulin and α-lactalbumin). FTIR spectra also showed noticeable difference between the secondary structure component of raw and modified WP. Finally, the structural micrographs of raw and modified WP from SEM and TEM analysis also confirmed the adequacy of modification of WP employing non-thermal techniques. The modified WP revealed smaller, regular and more homogenous and ordered structures compared to untreated sample.
•DA and IR roasting showed impact on BCS oil yield and chemical properties.•Roasting favored pigment transfer and changed the color of BCS oil.•DA roasting was more effective than IR roasting in ...improving oil quality.•HMF, BI, and OSI were increased by DA roasting at high temperature.•Recommended DA roasting condition is 180 °C for 10 min.
Black cumin seed (BCS) is a novel oil source with potential health benefits. This study investigates the influence of infrared (IR) and dry air (DA) roasting (140, 160 and 180 °C for 5 and 10 min) on BCS oil quality characteristics. Results revealed that the oxidative stability index (OSI), Maillard reaction products (MRPs), chlorophyll and carotenoid contents were increased while acid value (AV), peroxide value (PV) and color values were decreased in DA roasted (180°C for 10 min) BCS oil compared to other DA and IR treatments. DA and IR roasting slightly influenced the fatty acid composition (FAC) of BCS oils. FTIR spectra showed minor changes in peak intensities (at 2854, 2929 and 3008 cm−1) of DA and IR roasted BCS oils. DA roasting proved more effective than IR roasting. The oil from the DA roasted BCS at 180°C for 10 min had significantly higher oil quality and oxidative stability.
•Analytical TGA–FTIR and Py–GC/MS were conducted on pyrolysis process of alkali lignin.•Drying, fast degradation and slow degradation were the main three stages of alkali lignin pyrolysis.•The ...aromatics and phenols were the dominant components according to the FTIR spectrum.•The activation energy was raised from 124 to 721kJ/mol as the conversion rate increasing.•The guaiacol type (G-), phenol type (P-), syringol type (S-), and catechol type (C-) phenolic compounds were the main products from Py–GC/MS experiment.
Alkali lignin, an aromatic polymer extracted from soda pulping black liquor, is considered to be a potential source of phenolic-rich bio-oil using pyrolysis technology. This paper investigated the pyrolysis behaviors and kinetics of alkali lignin using thermogravimetric analyzer coupled with Fourier transform infrared spectrometry (TGA–FTIR) and pyrolyzer coupled with gas chromatography/mass spectrometer (Py–GC/MS). Results showed that the pyrolysis process of alkali lignin consisted of the three stages: drying stage, fast degradation stage and slow degradation stage. The weight loss rate reached its maximum value of 0.2448 mass%/°C at the temperature of 327°C. The aromatics (at 1512cm−1) and phenols (at 1261cm−1) were the dominant volatile components according the FTIR spectrum. As the conversion rate increased from 0.05 to 0.9, the activation energy estimated from Flynn-Wall-Ozawa (FWO) method, was raised from 124 to 721kJmol−1. The phenolic compounds, namely guaiacol type (G-), the phenol type (P-), the syringol type (S-), and the catechol type (C-) were the main products from Py–GC/MS experiment. The total phenols and the G-type phenols reached their maximum contents of 78% and 63.43% at 500°C, respectively. The content of S-type phenols decreased from 17.63% to 10.2% as the temperature increasing from 400°C to 700°C, while the contents of P-type and C-type phenols increased from 0.81% to 8.16% and 0.12% to 3.11%, respectively.
•Straw characterization was intended for bioethanol, biochar, compost and mushroom production.•Straw of 18 prominent rice cultivars was characterized though biochemical, SEM, FTIR.•Straw was grouped ...for production of biochar, bioethanol, compost, mushroom production.•Study showed the potential of straw for large and small-scale industrial applications.
Rice straw is a useful bio-resource with worldwide annual production of approximately 731 million tons. However, this valuable biomass is unfortunately burnt on field as waste that causes air pollution, global warming, plant nutrient losses and environment menace. About 60% of rice straw produced in Asia in general and India in particular is burnt in field. As for the basic requirement to predict their suitability for best alternative industrial uses biochemical, morphological and chemical (functional group) characterization of straws of 18 most widely grown rice cultivars from eastern region of India was carried out. Biochemical characterization was done on the basis of cellulose, hemicellulose, lignin and silica content. The surface morphology of straws was observed through Scanning Electron Microscopy (SEM), while, presence of functional groups were analyzed through Fourier Transform Infrared (FTIR) spectroscopy. Primarily, quantified biochemical profiles were used to group cultivars for best alternate uses of straw like bio-ethanol, biochar, compost and mushroom production. Morphological feature (from SEM) of straw and functional group (through FTIR) were used to support the grouping. Cultivars with higher hemicelluloses and cellulose with low to medium lignin and Si were better suited for bio-ethanol production while, straw having higher lignin and low to medium cellulose and hemicellulose were selected for biochar. Therefore, considering all the three characterization methods (chemical composition, morphological features, presence or absence of functional groups), we found straws of rice cultivars, Tapaswini and IR 64 were best suited for bio-ethanol and biochar production, respectively. There are overlapping as well as contradictory observations found during grouping, when the three approaches were followed together. This indicate that the grouping of straw for better alternative uses could be done by biochemical and morphological characterization but this should be validated in small scale at farm or factory level for final recommendation.
•TGA–FTIR system was equipped for the co-pyrolysis of sewage sludge and oil shale.•Activation energy was calculated by Kissinger–Akhira–Sunose and Starink methods.•The co-pyrolysis characteristic ...parameters were researched.
TGA–FTIR system was equipped under N2 for the kinetics behavior characteristics of sewage sludge (SS) and oil shale (OS) blends during co-pyrolysis. The SS was blended with OS in the range of 10–90wt.%, and then heated from 105°C to 1000°C at 10, 20 and 30°C/min under N2 atmosphere with a flow rate of 80ml/min. Two model-free methods, Kissinger–Akhira–Sunose (KAS) method and Starink method, were used to study their co-pyrolysis kinetics. There existed promoting effects on the degradation of oil shale during co-pyrolysis. The absorption of hydrocarbon became stronger with adding 10% SS. The best proportion of SS was selected as 10% due to better pyrolysis performance of OS and lower apparent activation energy (253.6kJ/mol obtained by Starink, 253.3kJ/mol obtained by KAS). The results afford a theoretical groundwork for the co-pyrolysis technology of SS and OS and the development of their thermochemical conversion systems.
•Two distinct methods allowed cellulose with different crystallinity to be obtained.•The alkaline treatment was adequate to remove hemicellulose.•X-ray diffraction showed the presence of type I ...cellulose.•Rose stems can be exploited to extract crystalline cellulose.•The proposed method allowed cellulose nanofibers to be produced.
The objective of the study was to explore the utilization of residual Rose stems as a source of cellulose nanofibers (CNFs). The CNFs were obtained by a so-called conventional method and another one proposed in this study. They were characterized by Fourier-Transform Infrared spectroscopy (FTIR), X-ray diffraction, scanning, and transmission electron microscopy (SEM, TEM). Changes in FTIR spectra indicate that conventional treatment adequately removed hemicellulose and lignin from the surface of the fibers. The degree of crystallinity of CNFs was 56.2%. The peaks observed in X-ray diffraction patterns refer to the presence of Type I cellulose. Results are promising for taking advantage of agricultural residues for the isolation of CNFs and their application in polymer matrices as reinforcement material.
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